I've tried on 2 seperate occasions 8 months apart to use rejuvaplex on my head (i use it on my skin religiously)

Both times around the 2 week mark i've begun to shed like crazy in the areas I apply it (right temple and both sideburns), it cant be a coincidence, the rejuvaplex is causing this for sure. I quit last time at this point because of the shed, and i'm feeling I should quit this time, unless somehow the shed is good?

It could be a positive shed if you're not experiencing a mpb itch during it. I don't have experience with Rejuveplex itself but I've experienced firsthand that regrowth occurs after an initial shedding phase. I'm sure CS can explain more on what the topical might be doing.

I have as well been using Rejuveplex for about a month now with ahk-cu added in from hairevo. I am also on the entire immortal regimen plus a bit of taiean protocol. About 3-4 days into the regimen plus rejuveplex, i to experienced a shed of the sideburns as well as the frontal part. But maybe a week in or a little longer i saw a bit of regrowth starting on the hairline. My upper sideburns were always really thin, but now it looks like they are actually filling in and getting some solid regrowth. If i were you, i would keep using it and not worry about the shed too much. After all it might be a good thing. Ill report back in a couple of months on the progress.